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Comparative Study of Surface Treatment Procedures for Dental Implants
12-32Views:371Nowadays, the most common type of implant in dentistry is a partial tooth replacement, such as a crown, or a complete tooth replacement. Today, many manufacturers offer implants made of a wide variety of materials and designs. These restorations must meet strict standards, one of the most stringent being surface roughness. Since proper bone-to-implant contact only occurs with adequate surface roughness, several methods are used to achieve the correct value. After reviewing the results of experiments carried out by several research groups, it is concluded that the surface roughness, the shape of the implant fixation screw, the shape of the thread and the thread elevation used to achieve the desired roughness together determine the success of the implantation. The average surface roughness required for osseointegration is considered to be optimal for values between 1 and 100 µm. In most cases, the surface roughness of commercially available dental prostheses is Ra 1-2 µm, but this can be modified by various grinding, acid etching and polishing processes to suit the application. Acid etching is a common technique for roughness reduction, which is the most effective in reducing surface roughness of dental restorative materials (mostly titanium alloys), thus bringing the roughness within the desired range. The result of acid etching is influenced by the concentration of acid, the temperature of the acid bath and the time spent in the acid. The acid used for the surface treatment is important and is most commonly sulphuric acid, hydrochloric acid or hydrogen fluoride (HF) and combinations of these. The study shows that the most optimal results are obtained with HF. Replacements are nowadays largely made by additive manufacturing, which allows for customised replacements and, due to dimensional accuracy, reduces the time and cost of post-processing, i.e. the surface treatment can be used to achieve the desired surface roughness and size at the same time. As a result, newer materials are being used for clinical prostheses and surface treatment should be applicable to all materials. The most optimal solution is a combination of grit blasting and acid etching. With this technology, the surface roughness for all materials reaches the optimum value of 1-100 µm, sometimes 1-2 µm, but can be further reduced below 1 µm by polishing. The study investigates the role of surface roughness, the surface roughness should only be reduced up to a certain value, approximately 0.5 µm, as smooth surfaces have limited or no potential for osseointegration.
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Mechanical Testing of 3D Metal Printed Stainless Steel Specimens
7-13.Views:325Additive manufacturing (AM) is a cutting-edge production method, which has come a long way since its first introduction in the ’80s. Back in the days its usage was very limited to stereolithography, and was only able to make weak structures, so it only worked for visualization. Four decades later it is one of the leading research fields in production areas, because of its flexibility and its ability to make almost any complex geometry. However, no matter how powerful it is, it is not omnipotent, there are certain size and shape restrictions even this method must apply to.
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The Future of AI-Integrated Project Management: A Structured Literature Review Based Risk Identification
42-67Views:837The evolution of AI is changing the landscape of project management. The integration of AI into project management brings many advantages, yet it is also accompanied by prominent weaknesses and serious challenges. In addition, rapidly evolving technologies continue to transform the field’s dynamics. These evolving dynamics result in ambiguity about the current state of the field, and consequently, create an uncertainty regarding a roadmap for future advancements. The purpose of this paper is to address this challenge by developing a well-grounded conceptual insight that identifies the risks associated with AI adoption in project management, guiding both academia and industry towards a structured approach to its future advancements. This paper conducts a detailed structured literature review, adhering the PRISMA protocol, to evaluate the impact of AI on key facets of project management, its potential benefits and implementation challenges. Then it analyzes the literature and synthesizes the key findings. Finally, it conducts comprehensive analysis to identify both positive and negative risks i.e. opportunities and threats. This in-depth analysis and its findings enable us to understand the nature of the risks, and how those can be harnessed or mitigated to advance the field. Furthermore, it provides both academia and industry the foundation to plan improved risk mitigation strategies and to develop a structured adoption framework. This study is expected to make a significant contribution to the advancement of the field.
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Implementation of Lean management Practices in Azerbaijan (on the Example of a Private Company)
30-40Views:286Organizations are facing crucial modifications as global market and conditions change day after day. To keep up with fast changing realities, it’s important to apply innovation decisions to the current stage of organizations. Lean management consolidates tools and techniques to revert from traditional way of operating to the new human oriented one. In the carried-out research its outlined, human resources management plays a big role in spreading and supporting lean initiatives. It was suggested that, Lean and Human resources management are compatible and should work together to obtain sustainable success by implementation of an innovation approach such as Lean. Both lean management and human resource management focus on the same goals with different methods in terms of control of businesses. All positivist approaches and practices are included in these approaches and practices, which are developed with a focus on the interests of the community, in order for the process to be concluded positively. The employee-centred management approach of human resources management is crucial to lead and maintain good environment in the teams. For this reason, in the lean management philosophy, it is aware that the corporate structure has responsibilities in terms of training the employees, eliminating their problems and supporting them in struggling with the responsibilities they undertake. This paper is quantitative, online survey has been conducted with employees of a private company in Azerbaijan and results were analysed in statistical analysis software SPSS and relevant suggestions and recommendation were given for reorganization to enable lean friendly environment on a sample of the given company.
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Development and Characterization of Sisal Fiber Reinforced Polypropylene Composite Materials
348-358Views:705In most of the developing countries, plastic polypropylene is not fully recycled and converted in-to use after it is once used. Sisal fiber is also widely available in different developing countries like Ethiopia. Adding this two materials and developing automotive interior part was taken as a primary motive for it reduces cost and is environmentally friendly. Thus, the main purpose of this research is to develop composite material from natural fibre (sisal fiber) reinforced with recycled plastic waste (polypropylene) for interior automobile accessories specifically for internal door trim panel application. This research examines effect of fiber length, fiber loading and chemical treatment of fiber on the physical and chemical properties of the sisal fiber reinforced polypropylene (SFRPP) composite material. The waste polypropylene and the treated and untreated sisal fiber with variable length and weight ratio (fiber/matrix ratio) were mixed. Flammability of sisal fiber reinforced Polypropylene (SFRPP) composites material was examined by a horizontal burning test according to ASTM D635 and chemical resistance of the sisal fibre reinforced PP composites was studied using ASTM D543 testing method. The result on the flammability test shows that treated fiber has lower burning rate than untreated fiber and decreases with increase in fiber length and fiber loading. The resistance of the composites to water has increased as the fiber length increases and decreased as the fiber loading increase. Generally, SFRPP composite is found to have better resistance to water than NaOH and H2SO4 and treating the fiber has brought considerable improvement on chemical resistance of the composite. Fiber loading and fiber length has positive and negative effect on the flammability of the SFRPP composite respectively.
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The Effect of Administrative Empowerment on the Organizational Effectiveness of Bank Employees
13-21Views:475This study seeks to identify the level of the impact of administrative empowerment in its dimensions on the organizational effectiveness in the banking sector in Syria. In order to verify the objectives, develop and test the validity of the hypotheses, the descriptive approach was adopted. The study found that there is a statistically significant effect of the dimensions of administrative empowerment on the organizational effectiveness of workers in banking sector.
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A Case Study on Human Resource Management Practice of a Sport Organization
410-425Views:1172Human resource with the adequate ability and skills is of decisive importance in all organizations, irrespective of the field of activity in which they operate. It is no different with the life of sports organizations. The human resource management of sports organizations is peculiar which is influenced by, on the one hand, the operating form of an organization, on the other hand, the nature of employment. Those well-known jobs can be also found in the sport organizations which are necessary to operate an organization and carry out the general tasks, at the same time, the amateur or professional athletes turn up as specific human resources. Aim of the study is to explore the specific characteristics of the human resource management of a particular organization, namely Debreceni Egyetem Atlétikai Club Sport Nonprofit Közhasznú Kft. (University of Debrecen Athletic Sport Non-profit Public Benefit Purpose Ltd., hereinafter: DEAC Ltd.), primarily focusing on the traditional HR functions. After reviewing the domestic and international specialized literatures, the practice of the examined sport organization will be described by means of case study, document analysis and managerial interview methods. Based on the results, it can be determined that there is no separate HR manager in case of the examined sport organization, due to its size, but the managing director carries out the tasks as an economic and HR manager in one person. From the aspect of organizational operation, the practice of HR functions is similar to the practice of other SME business organizations, at the same time, the management of athletics as human resources means its specific characteristic where the managements of labour supply, career and talent has other interpretation.
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Application of Team Coaching Tools for University Education – Case Study
445-456Views:699In 2010 the innovative Finnish higher education system (Tiimiakatemia – Team Academy) was launched at University of Debrecen Faculty of Economics and Business, which was also awarded by OECD and has been run at JAMK University of Applied Sciences in Jyvaskyla since 1993. In this system, we create team entrepreneurs who have to work together in teams. In this research the authors would like to look at how we can use the team coaching tools as a part of this model in our team entrepreneur education system to build high performing teams. Tuckman named five stages of team formation: forming, storming, norming, performing and adjourning. A new team cannot be expected to perform as an excellent team when it first comes together. It takes time forming a team, and they often go through recognizable stages as they change from being a collection of strangers to a united group with common goals. You have to understand it at first, than you can help your team become effective more quickly. Authors of this study work as team coaches in Team Academy Debrecen. In the last 6 years we have worked with several teams and experienced how group dynamics present at the teams and change through the learning process. We have faced with great storming period at different teams and managed to build high performing entrepreneur teams as well. Our experiences are introduced as case studies, after analysing, consequences will be concluded. As in the EFQM model we can find that to survive in the global competitive markets companies need the best teams for the best results.
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Segmenting the Impact of Organizational Structure and Leadership on Project Resilient and Project Success in the Ethiopian Construction Industry: a FIMIX-PLS & PLS-POS Approach
73-103Views:420This research looks at the vital roles of leadership and organisation design in the attainment of project resilience and success in the construction sector. Informed by contemporary theories on organisational resilience and leadership, a framework was developed and rigorously tested against data using Partial Least Squares Structural Equation Modelling (PLS-SEM) and with more advanced techniques of segmentation (FIMIX-PLS and PLS-POS) to identify and take into consideration unobserved heterogeneity. Using data collected from project professionals, resilient leadership and adaptive organisation design were shown to be critical to project resilience, but the effect of leadership and organisation design on project resilience differed from segment to segment as well as across demographics. The ex-post analysis suggested that the awareness of resilience, practical experience and higher education exacerbated the relationships between aspects of resilient leadership and project resilience, as well as between adaptive organisation design and project resilience. The analysis also showed that relationships between leadership, organisational structure, and resilience can be mediated by demographic factors, such as awareness, experience, and education. The findings highlighted the importance of fostering inclusive, participative type leadership styles and continuous forms of experiential learning to enhance resilience outcomes. The value of specific indicators such as team participation in decision making or the leader's self-confidence was also identified as being critical aspects of resilient organisational structures and effective leadership. The implications of this study were important for each group of stakeholders: organisations should encourage resilience-based leadership, experiment with multi-dimensional flexible team structures and create a culture of continued, experiential learning and communications as knowledge and industries evolve. The theoretical contributions that validated the effects of segments of latent variables and offered insight into the added value of using segmentation were positive contributions to theory. Limitations, such as sample size and sector, stimulate avenues for future work and in particular reinforce the case for longitudinal, cross-sector research to build sectors’ internal and external constructs of project resilience. Future research needs to apply multi-facilitated empirical, qualitative and advanced analytics means to enable further quantification, and complexity in project survival, success and resilience.
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Long Container Dwell Time at Seaport Terminals: An Investigation Study from a Consignee Perspective
Views:897Many companies are concerned about the problem of increasing average dwell time for their import containers at the port of the final destination and therefore incurring additional shipping costs in form of demurrage charges for the port administration and detention charges for the shipping line. Previous studies have addressed this topic by analyzing terminal operations and evaluated its effects on port productivity and competitiveness; however few studies have explicitly explored long container dwell time causes from a consignee perspective. This research aims to identify the causes of long dwell time for the import containers at port storage yards for one of the leading FMCG companies in Jordan. To that end, the data of import containers whose stay at the terminal exceeded the free storage days in the period between 2019 and 2020 were collected by referring to the set of shipping documents and reviewing the correspondences between the consignee and other parties in the supply chain. Based on the timelines that have been analyzed for each case of delay to the collection of shipping documents in consideration with the payment terms, as well as the clearance and delivery timelines, ten causes for the long container dwell time have been identified and classified into three main categories according to the types of flow in the supply chain; five causes related to information flow, two causes related to cash flow, and three causes related to physical flow. The impact of these causes has been evaluated using the demurrage and detention charges as a measure indicator and the findings of this research have also revealed that the causes related to cash flow have a greater impact than the other types of causes.
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Current Challenges in the Regulation of CO2 Emission of Road Vehicles
738-742Views:402Today, as part of the fight against climate change, regulations on greenhouse gas emissions are gaining significantly higher attention. Our work focuses on the European Union legislation on carbon dioxide emissions from road vehicles, with special emphasis on the target values. Current changes in CO2 measurement methods, as important issues of the regulations, are also reviewed within this article.
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Dynamic Tests on a Series Wound DC Motor. Simulation of the Braking of the Vehicle Driven by the Motor
15-20Views:250In the following we present the role and contribution of vehicle dynamics simulation to vehicle development in the University of Debrecen Faculty of Engineering. We present the input technical parameters which are necessary for the simulation of the series wound DC motor – which drives the vehicle – and also the procedure for their measurement together with the results of dynamic test measurements on the motor. The latest version of our vehicle dynamics simulation program –which is capable of the simulation of braking too – is also presented here.
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The Role Of Leader In Work Addiction
85-97Views:518Over-attachment to work is an increasingly common phenomenon in the lives of people in organisations, and can also be a condition of work addiction. Whoever becomes involved in an organisation, be it a subordinate or even a manager, work addiction has a number of negative consequences at both individual and organisational level. Without being exhaustive, work addiction can have an impact on organisational performance, organisational effectiveness, workplace conflict, career prospects, health maintenance. In this paper, we aim to highlight the most relevant publications from the last five years to report on the impact in an organisation when work addiction arises among subordinates or managers, and how different leadership styles are associated with work addiction among organisational members. The publications were retrieved from Google Scholar and Scopus, and the results of 19 articles are presented in this paper after a review of 263 papers retrieved. The results show that transformational, servant and ethical leadership styles have ambiguous effects on work addiction, unlike laissez-faire or abusive leadership styles, the former enhancing and the latter reducing the incidence of work addiction in an organisation. Work addiction of managers also has a dual effect: on the one hand, it can enhance creativity, but it can also increase turnover among subordinates. Social support from the manager can be an antidote to subordinates' work addiction, but this effect may be modified by the quantity and quality of interaction between manager and subordinate, the sense of meaningfulness of the work, or even the organisational culture. Overall, the manager, as a key actor, can have an impact on work addiction in the organisation, but there is not always a consistent position in the research on the cases and the way in which this is done, which calls for further research in the future.
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Full-Scale Tests of Pipeline Girth Welds Under Complex Cyclic Internal Pressure and Static Bending Loading Conditions
76-82Views:337The critical elements of high-pressure hydrocarbon transporting pipelines are often the girth welds, which are subjected to complex loads. The aims of our research and this paper are to introduce our full-scale pipeline fatigue and burst tests applying cyclic internal pressure and superimposed external bending stress on girth welds, furthermore, attracting the importance and the applicability of the investigation results. A unique testing system was built to study the behaviour of pipeline girth welds under simultaneous loads. The tests were evaluated using video camera recordings, internal pressure vs. burst time functions and failure pressure values.
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Stationary and mobile particulate matter concentration measurement in Miskolc
338-344Views:299A stationary and mobile device based on a low-cost dust sensor (Plantower PMS7003) was used to study particulate matter (PM) concentration in Miskolc. The stationary device was placed at the automatic monitoring station of the National Air Quality Measurement Network (OLM) in Martintelep, Miskolc. The mobile device was used to walk 4 streets along a square route with a total length of 800 m. Measurements were made on two days (September 9 and 11) between 7am and 9am, which according to preliminary experience coincided with the morning rush hour. The access route includes the OLM monitoring station, a busy road, two bypasses, a parking lot, and a smaller roadway blocked by traffic. The measured PM1, PM2.5, PM10 concentrations of the mobile device were interpolated on a circuit-by-circuit basis in ArcGIS, and conclusions were drawn for the area. The concentration of stationary and mobile devices was compared.
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Enhancing Customer Experience in Car Servicing: Insights from Indian Markets
113-123Views:302This descriptive research has attempted to assess customers' satisfaction with services offered by car servicing firms in India. The researcher administered a structured questionnaire to 300 company customers, selected using the Systematic Random Sampling technique. Data collected were analyzed using SPSS, applying the analytical tools of Frequency, Percentage, Mean, factor analysis, cluster analysis, Chi-square and Correspondence Analysis. Results of the study have revealed that the caring nature of servicing staff, the quality of services and service personnel, and the convenience and comfort offered to customers have been identified as the most important factors affecting customer satisfaction.
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Examination of the Physical Activity of Amateur and Hobby E-sport Players
Views:670With the spread of computers and the Internet, e-sports became a fast and dynamic growing sector with a significant market and economic potential. Its importance is demonstrated by the fact that its growth is now outstripping some traditional sports or other industries. E-sports users are sedentary in front of a computer during both competition and training, so their health is determined by the amount of physical activity they do when they are not in front of a computer. The primary aim of this research is to investigate the physical activity of e-sports users at different levels. In addition to this, I considered it important to investigate what games the players I interviewed compete in, how much time they spend playing and how they improve their skills. I conducted an online questionnaire survey in the University Electronic Games (UEG) online tournaments organised by the University of Debrecen. The participants in the survey fully met my criteria, as most of them were amateur or hobby e-sports players, so I obtained relevant data from their answers. Based on the participants' responses, it can generally be said that they engage in health-enhancing physical activity. However, it should be remembered that not only the rise in popularity of e-sports, but also the increasing digitalisation of society is contributing to the rise in sedentary lifestyles. In the future, it would be important to change the way gamers exercise, which until now has been predominantly to develop their digital video game skills. Physical activity and other health-related behaviours need to be integrated into the training routines of gamers - e-sports players, so that playing sports could become a natural pastime alongside e-sports.
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Developing a Financial Sustainability Model of the Performance Indicators Applied by Jordan Water Company (Miyahuna)
75-87Views:519Jordan is now facing real challenges to satisfy the current population water needs due to limited resources. Moreover, unfortunately, as a result of the increased demand for water in developing countries, water resources become scarce, thus, the sustainable management of water resources is very important everywhere and especially in these areas. The Ministry of Water and Irrigation in Jordan is aiming to improve both its quality of service and financial sustainability, therefore, it started to apply the performance measurement system developed by the International Water Association (IWA) to monitor its performance towards achieving these goals. In this article, a model connecting a financial sustainability indicator (operating cost coverage ratio) with other performance indicators applied by the ministry is developed. To assess the performance indicators and to build the model secondary data are collected from the targeted company, the data are analyzed using SPSS and Excel computer programs. Non-revenue water (NRW), speed of repair of bursts, and training per employee are found to be the indicators that have a major impact on Miyahuna’s financial sustainability, the NRW is found to have a negative relationship with the financial sustainability, whereas the other two indicators have a positive relationship. As a conclusion, reducing the NRW and increasing both the speed of repair and training per employee are recommended, by applying some methods that continuously diagnose problems in the water systems and defining clear and strict policies to control the water theft. Furthermore, using Active Leakage Control (ALC) methods, providing the needed equipment, tools and resources, and adopting new methods for training.
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Economic Effect of the Coronavirus on the Companies Involved in Car and Automotive Parts Trading, and Manufacture of Tires of Hungary, Including Szabolcs-Szatmár-Bereg County, in Respect of 2020
1-12Views:493In Hungary the wake of the first wave of the Covid-19 epidemic (March 2020), caused a decline in demand for goods and services in most sectors. There were sectors (accommodation services, art, recreation, etc.), which were economically severely burdened by the imposition of restrictive measures, and there were some (financial services, communication), which experienced the change positively. In our research, our goal was to assess the changes caused by the Covid-19 epidemic in the property, financial and profitability situation of the companies involved in car and automotive parts trading, and tire manufacturing, in Hungary, and within the country, in Szabolcs-Szatmár-Bereg county. We established three hypotheses: (1) As a result of the spread of coronavirus epidemic, in Hungary and in Szabolcs-Szatmár-Bereg county as well, the profitability of companies of NAICS codes 441 (car and automotive parts trading) and 4231 (wholesale of road vehicles and parts), decreased. (2) The outbreak of the epidemic had a negative impact on the liquidity of companies established in Hungary, including Szabolcs- Szatmár-Bereg county. (3) As a result of the Covid-19 epidemic, the resource structure of Szabolcs-Szatmár-Bereg county companies, analysed in the framework of research work, transformed. To prove or disprove these, secondary research was used. Finally, we put forward conclusions and proposals for the management of the companies active in this industry.
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Design of Experiments Application for Machining Process Analyse
257-265Views:266In this contribution are results from machining of the aluminium alloy by spiral router. The experiment was designed as full 3 - factors and 2-levels process and for evaluation of input factors to output parameters – Fx and Fy components were used Paret´s diagram and Lorentz´s line. The input parameters were: revolution speed (4000/min. and 6000/min.), working engagement of a cutting edge (depth of cut) ae (1 mm and 3 mm), back engagement of a cutting edge (with of cut) ap (5 mm and 15 mm) and down (climb) milling.
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Speed Variation along an Imposed Linear Trajectory, for Robotic Arms Motion
495-502Views:235The paper describes a method of speed (velocity) computation, named mixt profile, during a motion upon an imposed linear trajectory. The method assures an accurate positioning at the end of motion (movement), in a well determinate time lapse. The described method is linked with position vector computation, about a robotic arm.
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Investigation on Double Oxide Film Initiated Pore Formation in Aluminum Casting Alloys
141-153Views:595The most common, and in fact, the most deleterious defects of aluminum casting alloys are the so-called double oxide films or bifilms, which have a central role in porosity formation, as they can easily unfurl and inflate into pores during the solidification of the alloys. Sr addition is generally used in the foundry industry for the modification of the eutectic Si phase of hypoeutectic Al-Si alloys. However, Sr microalloying usually leads to an increased pore formation tendency. As bifilms are preferred sites for pore formation, it should be expected that Sr additions have a significant effect on the number and/or the structure of double oxide films present in the melt. In this work, the relationship between Sr-concentration and the susceptibility to pore formation has been investigated through the evaluation of melt quality of melts which had different levels of Sr. The bifilm content of the melts was investigated by the analysis of K-mold specimens and X-ray computed tomography (CT) of reduced pressure test (RPT) samples. It was found that liquid alloys with a higher Sr concentration had a significantly greater tendency to pore formation, which can be explained by the presence of a larger number of bifilm defects in the liquid alloy.
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Advancing Sustainable Waste Management through National Recycling Rate under SDG 12.5.1
61-72Views:567Solid waste management remains a pressing environmental challenge in both developed and developing nations. Recycling has been promoted globally as a key pathway to sustainability, yet recycling rates often provide only a partial picture of performance. In many contexts, challenges such as poorly regulated recycling policies, informal sector dominance, and practices that prioritize profit over environmental sustainability limit progress towards Sustainable Development Goal (SDG) 12.5.1, which tracks the national recycling rate. This study investigates the extent to which recycling rates reflect sustainable waste management and identifies the underlying factors that influence their effectiveness. The major objective of this study is to evaluate recycling rates as an indicator of sustainable waste management. This is further specified by: (i) examining recycling practices in selected countries (Germany, South Korea, USA, Brazil, and India), (ii) identifying key drivers and barriers that influence recycling performance, and (iii) assessing the implications of recycling rates for sustainable waste management systems. The study employed a mixed-methods approach, combining secondary data analysis, comparative country assessment, and policy review. Results show that recycling rates are useful but insufficient as a stand-alone measure of sustainability, since they are influenced by broader elements such as policy enforcement, economic incentives, public participation, and market structures. The findings highlight that Nigeria’s recycling rate remains significantly low compared to leading economies, underscoring the need for integrated waste management reforms. This research contributes to environmental management discourse by demonstrating that while recycling rates provide a benchmark for SDG 12.5.1 monitoring, they must be interpreted alongside contextual drivers to ensure meaningful progress towards sustainable waste management.
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Sustainable Energy in Aviation with Reverse FMEA Analyses
29-40Views:423This research aims to identify and evaluate the key challenges and obstacles hindering the adoption of sustainable energy in the aviation industry. The outcomes and insights derived from this research will be synthesized to provide a comprehensive overview of the opportunities and suggestions for the adoption of sustainable energy in the aviation industry. The objective of this study is to help the aviation industry’s shift toward more sustainable energy sources in order to reduce its environmental footprint and mitigate the effects of climate change.
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Potentiodynamic Study of the Effects of Nickel on The Electrodeposition of Zinc from Chloride Media
15-24Views:346Abstract. The potentiodynamic experiments of the nickel effects on the zinc electrodeposition have been done to understand the impact of Ni impurities on the electrowinning of Zn from spent pickling liquor. The nickel chloride solutions of Ni concentrations 90 and 1 g/dm3 were used as the electrolytes. The latter was also mixed with 90 g/dm3 Zn in the experiments. All the runs were carried out at room temperature with 40 mV/s continuous polarization speed and with 1/s sampling rate. It was observed that nickel electrodeposition from chloride media containing 90 g/dm3 Ni started with the generation of hydrogen bubbles, entirely blocking the cathode surface. Only a slight current development was observed until the polarization potential ~ -0,8 V. The visual observation showed bubbles also formed at the anode, which may represent chlorine and/or oxygen evolution. While, in the electrodeposition of nickel with only 1 g/dm3 Ni concentration in the electrolyte, metal deposition was hardly observed, but visible hydrogen bubbles constantly blocked the cathode surface. A similar tendency was observed in the mixed-solution electrolysis cell; the initial tiny bubbles accumulated at the cathode surface more than in the pure Zn solution. The enhancement of H2 evolution indicates how nickel deposition may contribute to the loss of useful current in the process of Zn electrodeposition. The mass of nickel deposited from the mixed solutions significantly decreases as the Ni concentration decreases in the electrolyte, while the mass of deposited zinc is relatively constant. It means that the purity of the produced Zn is appreciably higher – with respect to Ni – if nickel is efficiently eliminated from the solution before electrowinning.
